Heat-exchange apparatus



Feb. 1927.

v F. s. BENNETT HEAT EXCHANGE APPARATUS Filed Ausz. 4, 1926 IhvehtoT": Frank S. Ben'riett,

bg His Attovneg.

Patented Feb. 22, l927.

UNHTED STATES iterate? rear ossics.

FRANK S. BENNETT, OF SCHENECTADY, NEW YORK, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

HEAT-EXCHANGE APPARATUS.

Application filed August 4, 1926.

My invention relates to heat exchange ap- 5 face of the tubes.

My invention has for its object to so con= struct a heat exchange apparatus that one of the tube sheets may float, thereby permitting the tubes to be rigidly fastened to the tube sheets, allowing at the same time for expansion of the tubes without any danger of their becoming loose and thus leak.

The novel features of my. heat exchange apparatus are pointed out with particularity in the claim annexed to and forming a part of this specification. For a better understanding of my invention, reference may be had to the following description taken in connection with the accompanying drawing, in which Fig. 1 is a side elevation, with parts broken away, of a heat exchange apparatus embodying my invention; Fig. 2 1s a plan view of the heat exchange apparatus of Fig. 1; Fig. 3 is a detailed view of a single tube and its mounting, and Fig. 4 is a section on line 4-4 of Fig. 2.

Referring to the drawing there is shown a heat exchange apparatus,'wh ich is particularly designed for use as One section of a surface air cooler. In this cooler there are two tube sheets 1, a plurality of tubes 2 mounted between the tube sheets and water boxes 3 and at, each of which is rigidly connected to one of the tube sheets 1. The tubes 2 have radiating fins 5 on their outer periphery. (See Fig. 3.) These fins are preferably made of copper and are fastened to the tubes so as to have a good thermal contact there- 'with and are shown as wound on a spiral about the tube. The tube sheets have holes 6 therein of substantially the same outside diameter as the outside dimensions of the fins. The tubes may be placed in position in the cooler and removed therefrom through these holes 6. The tubes have enlarged end portions 7 of substantially the same size as the holes 6, whereby the tub-es are fastened in the tube sheets 1. I have shown these enlarged portions 7 as plugs fastened on the ends of the tubes by expanding the tubes therein as shown in Fig.3. The plugs may be fastened on the tubes in any well known manner. The enlarged end portions 7 may also be made in any well known manner. The plugs have screw threads 8 for screwing Serial No. 126,958.

them in the threaded holes 6 in the tube sheets, and a shoulder to receive a fibre gas ket 9 which makes tight the joint between the plug and tube sheet. I preferably prvide the tube sheets with holes 10 in addition to the holes 6, the holes 10 being of substantially the same size as the portions of the tubes 2 on which the fins are mounted, and alternate the small holes with the large holes 6. Only one end of each tube has an enlarged end 7 the other end portion 11 is of substantially the same size as the portion of the tubes. 2 on which the fins are mounted. These ends 11 of the tubes are expanded into the holes 10 of the tube sheets and are thereby securely fastened therein.

By alternating the enlarged end portions with the small end portions in each tube sheet and consequently the large and small holes in the tube sheets, ample material is left in each tube sheet for strength, and at the same time, the tubes can be spaced close together and thereby a maximum rate of transfer of heat can be obtained from the air to the tubes. If the device of the drawing is used as a condenser, then the maximum rate of transfer of heat would be obtained from the tubes to the air passing over the tubes. With holes 6 and 10 alternating in each tube sheet, each tube must be placed in position and removed through the tube sheet having the large hole 6 therein.

The tubes are supported substantially midway between the tube sheets by a supporting member 12 having openings 13 of substantially the same size as the outside dimensions of the fins. The openings 13 are provided with ferrules 14:. This central support is used to adequately support the tubes and to make them reasonably easy of removal,preventing them from dropping down and becoming entangled with the fins of other tubes. This support also acts as a guide when replacing a tube.

The cooler is mounted in a frame comprising members 15 extending in the direct on of the tubes and end members 16 and 17 fastened to the members 15. Each of the Water boxes 3 and 4: is boltedto the adjacent tube sheet. The box 3 has large outlet and inlet openings 18 to reduce turbulence tending to affect the distribution of water through the tubes. Partitions (not shown) are cast as usual in the boxes in order to form the number of water passes desired.

16 of the frame.

The water box 3 and the corresponding tube sheet are rigidly fastened to the end member The water'box t with its corresponding, tube sheet is fastened only at the middle of two opposite end members 17 by means of bolts 19. Consequently, the water box 4. and its tube sheet will float upon expansion or contraction of the tubes, flexing the steel members 17 which are so proportioned that they will deflect under a small load, no movement taking place between the tubes and the tube sheets. This feature is useful in my cooler, since the tube sheets are fastened to the frame, which has a different expansion than the tubes themselves, due both to differences in temperatures and differences in coefiicients of expansion of the materials of the tubes and frame.

I desire it to be understood that my invention is not limited to the particular arrangement shown and described, and I aim in the appended claim to cover all modifications which do not depart from the spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

In a heat exchange apparatus, a plurality of tube sheets, a plurality of tubes mounted between and having their ends fastened in said tube sheets, a frame comprising members extending in the direction of said tubes and end members fastened to said first mentioned members, one of said tube sheets being fastened to the end members at one end of theapparatus, the other of said tube sheets beingfastened only at the middle of two opposite end members at the other end of said a paratus, saidlast mentioned end members being flexible, whereby said tubes upon expanding or contracting will deflect said end members.

In witness whereof, I have hereunto set my hand this 2nd day of August, 1926.

FRANK S. BENNETT. 

